Fan control device

ABSTRACT

A fan control device is used for controlling at least one fan. The fan control device comprises a signal modulation unit and a shield unit. The signal modulation unit is used for providing a modulation signal and a duty status signal. The shield unit is coupled to the signal modulation unit and the at least one fan for receiving a standby voltage, the duty status signal, and the modulation signal, as well as for shielding the modulation signal or transmitting the modulation signal to the at least one fan according to the standby voltage and the duty status signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 201210465181.6 filed in China, P.R.C. on Nov. 16, 2012, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The disclosure relates to a control device and more particularly to a fan control device.

2. Description of the Related Art

Generally speaking, heat dissipation devices, such as fans or heat dissipation modules, are installed in most servers or computer systems in order to reduce the heat generated from the operation of the electronic components inside the servers or the computer systems, so as to enhance the work efficiency of the electronic components and the overall operational performance. The heat generated from the operation of the electronic components is directly absorbed by the heat dissipation modules through thermal conduction. The heat absorbed by the heat dissipation modules is dissipated to an external environment by the heat exchange of the cross-ventilation produced by the operation of the fans.

In controlling the operation of the fans, a pulse width modulation (PWM) generator is usually used for generating a pulse width modulation signal to control the operation of the fans. When the server or the computer system starts working, the pulse width modulation (PWM) generator starts with an initialization stage and performs initialized settings, and then the pulse width modulation signal is generated correspondingly for controlling the fans to operate under a rotational speed correspondingly.

However, when the pulse width modulation (PWM) generator starts with the initialization stage and before it finishes the initialization stage, all the pulse width modulation signals produced by the pulse width modulation (PWM) generator are at a high logic level. This causes the fan to start operating under a full rotational speed. Thus, power is wasted. Therefore, the controlling of the fan still needs to be improved.

SUMMARY OF THE INVENTION

The fan control device disclosed by the disclosure is used for controlling at least one fan. The fan control device comprises a signal modulation unit and a shield unit. The signal modulation unit is used for providing a modulation signal and a duty status signal. The shield unit is coupled to the signal modulation unit and the at least one fan for receiving a standby voltage, the duty status signal, and the modulation signal, as well as for shielding the modulation signal or transmitting the modulation signal to the at least one fan according to the standby voltage and the duty status signal.

In an embodiment, before the signal modulation unit finishes the initialization stage, the signal modulation unit provides the duty status signal at a high logic level and the modulation signal at the high logic level, as well as the shield unit shields the modulation signal of the high logic level according to the duty status signal of the high logic level.

In an embodiment, when the signal modulation unit finishes the initialization stage, the signal modulation unit provides the duty status signal at a low logic level and the modulation signal in a pulse form, and the shield unit transmits the modulation signal in the pulse form to the at least one fan according to the duty status signal of the low logic level.

In an embodiment, the signal modulation unit provides the duty status signal via a general purpose input/output pin.

In an embodiment, the shield unit comprises a transistor. The transistor includes a first end, a second end, and a third end. The first end of the transistor receives the standby voltage and the duty status signal. The second end of the transistor receives the modulation signal. The third end of the transistor is coupled to a ground end.

In an embodiment, the fan control device further comprises a power supply. The power supply is coupled to the shield unit for providing the standby voltage. The power supply is further coupled to the signal modulation unit and the at least one fan for providing an operating voltage required for the signal modulation unit and the at least one fan.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the detailed description given herein below for illustration only, and thus does not limit the disclosure, wherein:

FIG. 1 is a perspective view of a fan control device according to an embodiment of the disclosure; and

FIG. 2 is a perspective view of a fan control device according to another embodiment of the disclosure.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

In each embodiment mentioned hereinafter, the same numbers are used for representing the same or similar elements.

Please refer to FIG. 1. FIG. 1 is a perspective view of a fan control device according to an embodiment of the disclosure. A fan control device 100 of this embodiment is used for controlling fans 170_1˜170_N. The fans 170_1˜170_N are disposed in a server or a computer system, but the disclosure is not limited thereto. The fans 170_1˜170_N are used for dissipating the heat from the server or the computer system. N presents a positive integer greater than 1.

The fan control device 100 comprises a signal modulation unit 110 and a shield unit 120. The signal modulation unit 110 is used for providing a modulation signal VPWM and a duty status signal VWS. The signal modulation unit 110 is, for example, a pulse width modulation (PWM) generator. The signal modulation unit 110 is used for providing the modulation signal VPWM at a low logic level, at a high logic level, or in a pulse form.

In this embodiment, when the signal modulation unit 110 begins operating and starts with an initialization stage, the signal modulation unit 110 provides, for example, the duty status signal VWS at the high logic level and the modulation signal VPWM at the high logic level. When the signal modulation unit 110 finishes the initialization stage, the signal modulation unit 110 provides the duty status signal VWS at the low logic level. Also, the signal modulation unit 110 provides, for example, the modulation signal VPWM in the pulse form.

The shield unit 120 is coupled to the signal modulation unit 110 and the fans 170_1˜170_N for receiving a standby voltage VS, the duty status signal VWS, and the modulation signal VPWM. The shield unit 120 shields the modulation signal VPWM or transmits the modulation signal VPWM to the fans 170_1˜170_N according to the standby voltage VS and the duty status signal VWS.

For example, when one of the standby voltage VS and the duty status signal VWS is at the high logic level, or when both the standby voltage VS and the duty status signal VWS are at the high logic level, the shield unit 120 shields the modulation signal VPWM at the high logic level. In other words, the shield unit 120 does not transmit the modulation signal VPWM at the high logic level to the fans 170_1˜170_N.

Because the shield unit 120 shields the modulation signal VPWM at the high logic level, the shield unit 120 provides, for example, a signal at the low logic level to the fans 170_1˜170_N to cause the fans 170_1˜170_N to operate under the lowest rotational speed.

On the other hand, when the duty status signal VWS is at the low logic level, the shield unit 120 transmits the modulation signal VPWM to the fans 170_1˜170_N to cause the fans 170_1˜170_N to operate under a corresponding rotational speed according to the control of the modulation signal VPWM. Thereby, before the signal modulation unit 110 finishes the initialization stage, the fans 170_1˜170_N do not operate under the full rotational speed in order to avoid wasting power and to enhance the convenience in usage.

In this and some other embodiments, the signal modulation unit 110 includes a general purpose input/output (GPIO) pin, but the disclosure is not limited thereto. The signal modulation unit 110 produces the duty status signal VWS via the general purpose input/output (GPIO) pin. The standby voltage VS is, for example, a P3V3_STBY standby voltage.

Please refer to FIG. 2. FIG. 2 is a perspective view of a fan control device according to another embodiment of the disclosure. A fan control device 200 of this embodiment is used for controlling fans 170_1˜170_N. The fan control device 200 comprises a signal modulation unit 110, a shield unit 120, and a power supply 210. The coupling between the signal modulation unit 110 and the shield unit 120 as well as the corresponding operations, which can be referred to the descriptions of the embodiment in FIG. 1, are not mentioned herein again.

The power supply 210 is used for providing an operating voltage VCC and a standby voltage VS. The operating voltage VCC is the operating voltage required for the operations of the signal modulation unit 110 and the fans 170_1˜170_N.

The shield unit 120 comprises a transistor M. The transistor M includes a first end, a second end, and a third end. The first end of the transistor M receives the standby voltage VS and the duty status signal VWS. The second end of the transistor M receives the modulation signal VPWM. The third end of the transistor M is coupled to a ground end GND.

In this and some other embodiments, the transistor M is an N-type transistor. The first end of the transistor M is a gate of the N-type transistor, the second end of the transistor M is a drain of the N-type transistor, and the third end of the transistor M is a source of the N-type transistor, but the disclosure is not limited thereto. The transistor M is, for example, a P-type transistor or other types of transistors. For examples, the transistor is a bipolar junction transistor or a junction field effect transistor.

First, when the power supply 210 only provides the standby voltage VS (e.g. P3V3_STBY) and the standby voltage VS is supplied to the first end (the gate) of the transistor M, the transistor M turns on and the connection point 220 is conducted to the ground end GND.

Because the connection point 220 is connected to the ground end GND, the shield unit 120 can shield the modulation signal VPWM. In other words, the modulation signal VPWM is not transmitted to the fans 170_1˜170_N, and the shield unit 120 produces, for example, a signal at a low logic level to the fans 170_1˜170_N corresponding to the ground end GND. At this point, the power supply 210 does not provide the operating voltage VCC for the fans 170_1˜170_N and therefore the fans 170_1˜170_N do not operate.

Then, the power supply 210 provides the operating voltage VCC in order that the fan control device 200 and the fans 170_1˜170_N can start to operate. When the fan control device 200 starts to operate, the signal modulation unit 110 starts with the initialization stage and performs initialized settings.

In the initialization stage, the signal modulation unit 110 provides the duty status signal VWS at a high logic level and the modulation signal VPWM at the high logic level. The duty status signal VWS at the high logic level and the modulation signal VPWM at the high logic level are provided to the first end (the gate) of the transistor M of the shield unit 120 and the connection point 220 (e.g. the second end of the transistor M, i.e. the source) respectively.

Then, because the duty status signal VWS and the standby voltage VS received by the first end of the transistor M are at the high logic level, the transistor M turns on and the connection point 220 is conducted to the ground end GND. Thereby, the shield unit 120 shields the modulation signal VPWM at the high logic level. In other words, the modulation signal VPWM at the high logic level is not transmitted to the fans 170_1˜170_N.

At this point, the shield unit 120 produces, for example, the signal at the low logic level to the fans 170 _(—1˜170)_N corresponding to the ground end GND to cause the fans 170_1˜170_N to operate at the lowest rotational speed corresponding to the signal at the low logic level.

Afterwards, when the signal modulation unit 110 finishes the initialization stage, the signal modulation unit 110 provides, for example, the duty status signal VWS at the low logic level and the modulation signal VPWM in the pulse form. The duty status signal VWS at the low logic level and the modulation signal VPWM in the pulse form are provided to the first end (the gate) of the transistor M of the shield unit 120 and the connection point 220 (e.g. the second end of the transistor M, i.e. the source) respectively.

At this point, because the duty status signal VWS received by the first end of the transistor M is at the low logic level, the transistor M does not turn on and the connection point 220 is not conducted to the ground end GND. Thereby, the shield unit 120 transmits the modulation signal VPWM in the pulse form to the fans 170_1˜170_N to cause the fans 170_1˜170_N to operate under the corresponding rotational speed according to the control of the modulation signal VPWM.

Thereby, before the signal modulation unit 110 finishes the initialization stage, the fans 170_1˜170_N do not operate under the full rotational speed in order to avoid wasting power and to enhance the convenience in usage.

According to the fan control device disclosed in the embodiments, according to the standby voltage and the duty status signal provided by the signal modulation unit, the shield unit determines whether to shield the modulation signal provided by the signal modulation unit or to transmit the modulation signal provided by the signal modulation unit to the at least one fan. Thereby, the at least one fan can be prevented from operating under a full rotational speed when the signal modulation unit starts with the initialization stage and before the signal modulation unit finishes the initialization stage in order to avoid wasting electric power and to enhance the convenience in usage.

Note that the specifications relating to the above embodiments should be construed as exemplary rather than as limitative of the invention, with many variations and modifications being readily attainable by a person skilled in the art without departing from the spirit or scope thereof as defined by the appended claims and their legal equivalents. 

What is claimed is:
 1. A fan control device for controlling at least one fan, the fan control device comprising: a signal modulation unit for providing a modulation signal and a duty status signal; and a shield unit coupled to the signal modulation unit and the at least one fan for receiving a standby voltage, the duty status signal, and the modulation signal, as well as for shielding the modulation signal or transmitting the modulation signal to the at least one fan according to the standby voltage and the duty status signal.
 2. The fan control device according to claim 1, wherein before the signal modulation unit finishes an initialization stage, the signal modulation unit provides the duty status signal at a high logic level and the modulation signal at the high logic level, and the shield unit shields the modulation signal of the high logic level according to the duty status signal of the high logic level.
 3. The fan control device according to claim 1, wherein when the signal modulation unit finishes an initialization stage, the signal modulation unit provides the duty status signal at a low logic level and the modulation signal in a pulse form, and the shield unit transmits the modulation signal in the pulse form to the at least one fan according to the duty status signal at the low logic level.
 4. The fan control device according to claim 1, wherein the signal modulation unit provides the duty status signal via a general purpose input/output pin.
 5. The fan control device according to claim 1, wherein the shield unit comprises: a transistor including a first end, a second end, and a third end, the first end of the transistor receives the standby voltage and the duty status signal, the second end of the transistor receives the modulation signal, and the third end of the transistor is coupled to a ground end.
 6. The fan control device according to claim 1, further comprising a power supply coupled to the shield unit for providing the standby voltage, and the power supply is further coupled to the signal modulation unit and the at least one fan for providing an operating voltage required for the signal modulation unit and the at least one fan. 